public class PlanetUtil {
    public static double computeVolume(Planet1 p) {
        return 4 * Math.PI*Math.pow(p.radie, 3) / 3;
    }//computeVolume

    public static double computeDistance(Planet1 p1, Planet1 p2) {
        return Math.sqrt(Math.pow(p1.x - p2.x,2) + Math.pow(p1.y - p2.y,2) 
                    + Math.pow(p1.z - p2.z,2));
    }//computeDistance
}//PlanetUtil